The Hillsboro fuel-cell manufacturer will have to restructure millions of dollars in debt to survive.

The fuel-cell manufacturer lined up $73.5 million three years ago, a deal that emerged as the state’s largest investment round of 2011. Executives now say the company owes more than $100 million to at least 1,000 creditors, according to a Chapter 11 bankruptcy petition filed last week.

Its move to seek bankruptcy protection came a week after it shut down its Connecticut operations and laid off more than 250 employees.